Traditional undergarments and pajamas for men come in multiple varieties. Variants of these undergarments generally have a different waist size and shape (e.g. briefs, trunks, boxers, boxer briefs), etc. In these undergarments, the position of a genital opening is generally fixed and may not fit the man's physique or preference. If a man wears an undergarment according to waist size and/or shape of his choice, his genitals may not align with the genital opening. This limits the range of his choice and is also inconvenient for the wearer. Undergarments and pajamas for covering the groin and genital area include briefs, which are relatively form fitting and hold the genitals against the body, and boxers that are looser. Briefs provide some genital support, but also limit the circulation of air around the genitals. Neither boxers nor briefs seek to fit material between the genitals and the groin and/or legs of the wearer. There remains a need for improved undergarments and pajamas that provide an adjustable separation and free fit between the genitals and the groin and/or legs of the wearer.